Turbidity sensor

Abstract

The invention relates to the field of sensors, in particular to a turbidity sensor which comprises a tube body, a circuit board, a light source, a receiver and a refraction piece, the light source and the receiver are arranged on the outer side of the tube body and connected to the circuit board, and the circuit board is arranged on the side, away from the refraction piece, of the tube body. The tube body is filled with liquid to be measured, the light source emits main light rays propagating in the radial direction to serve as incident light rays, at least part of the incident light rays directly penetrate through the liquid to be measured and reach the refraction piece, after the incident light rays are totally reflected by the refraction piece for multiple times, emergent light rays propagating in the liquid to be measured in the straight line are formed, and the position of the receiver corresponds to the emergent light rays. And the detector is used for detecting the intensity of the received emergent light. According to the turbidity sensor, the light source and the receiver are arranged on the same side of the outer side of the tube body, and the refraction piece is arranged to enable the light direction to rotate, so that attachment and deposition of suspended solids in liquid to be detected on the surface of the turbidity sensor are inhibited, the service life is prolonged, and the detection sensitivity is improved by prolonging the optical path.

Description

Technical Field

[0001] The present invention relates to the field of sensors, and in particular to a turbidity sensor. Background Art

[0002] Turbidity is a measure of the degree of light scattering caused by suspended particles in a liquid. It is related to the concentration, particle size, shape, and material of the suspended matter in the liquid and is a key physical indicator in water quality testing. When incident light passes through a solution of a certain thickness, the intensity of the transmitted light and the turbidity of the solution conform to the Lambert-Beer law. The intensity of the outgoing light depends on the turbidity or concentration of the solution: high when the turbidity is low and low when the turbidity is high. The receiving photoelectric device converts the light intensity into an electric current, and the corresponding turbidity of the solution can be calculated. Currently, turbidity sensors are widely used in automatic cleaning equipment such as sweepers, dishwashers, and dishwashers. By detecting the turbidity of the liquid and automatically determining whether repeated cleaning is necessary, the intelligence of the equipment can be effectively improved.

[0003] Current devices typically use an opposed-beam turbidity sensor, where a light source and receiver are positioned opposite each other. Light from the light source travels straight through the test liquid before being received by the receiver. The intensity of the light received by the receiver determines the turbidity of the test liquid. However, this detector requires exposure to the test liquid environment and has a complex surface structure and low smoothness, which makes it prone to suspended matter deposition on the detector surface, affecting detection accuracy. Summary of the Invention

[0004] The object of the present invention is to provide a turbidity sensor which is less likely to cause deposition of suspended matter on the surface.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] A turbidity sensor includes a tube body, a circuit board, a light source, a receiver, and a refractive element. The light source and the receiver are arranged on the outside of the tube body and connected to the circuit board. The circuit board is arranged on the side of the tube body away from the refractive element. The liquid to be tested is filled in the tube body. The light source is used to emit incident light. At least part of the incident light directly passes through the liquid to be tested and reaches the refractive element. After being totally reflected several times by the refractive element, it forms an outgoing light that propagates in a straight line in the liquid to be tested. The position of the receiver corresponds to the outgoing light and is used to detect the intensity of the received outgoing light. The incident light is the main light emitted by the light source, and the incident light propagates radially along the tube body.

[0007] Optionally, the tube body is constructed as a tubular structure with two ends open, the light source and the receiver are arranged along the axial direction of the tube body, and the emergent light propagates along the radial direction of the tube body.

[0008] Optionally, the tube body is constructed as a transparent structure and has a smooth inner wall. The refractive element is fitly connected to the outer wall of the tube body and has a first reflecting surface and a second reflecting surface. The first reflecting surface and the second reflecting surface are both facing the inner wall of the tube body. At least part of the incident light directly passes through the liquid to be tested and forms a transfer light after being reflected by the first reflecting surface. The transfer light is directly directed to the second reflecting surface and reflected again to form the outgoing light.

[0009] Optionally, the refraction member is made of the same material as the tube body and is integrally constructed as an arc-shaped structure of the tube body. The refraction member has a connecting surface that fits against the outer wall of the tube body, and both ends of the connecting surface are respectively connected to the first reflecting surface and the second reflecting surface.

[0010] Optionally, the refraction member is integrally constructed with the tube body.

[0011] Optionally, the deflecting member is detachably connected to the tube body, and a central angle of the deflecting member is greater than 180°.

[0012] Optionally, the tube body is made of polycarbonate, and the angle between the second reflective surface and the axial direction of the tube body is any value between 40° and 55°.

[0013] Optionally, the angle between the first reflecting surface and the axial direction of the tube body is 45°.

[0014] Optionally, the first reflective surface and / or the second reflective surface of the refractive element is covered with a reflective material.

[0015] Optionally, the plurality of light sources form the incident light with visible light and infrared light, respectively, for detecting the turbidity and color depth of the liquid to be tested.

[0016] The present invention has the beneficial effects of providing a tube body to contain the test liquid, with the light source and receiver located outside the tube body, thereby separating the light source and receiver from the test liquid and preventing particles carried by the test liquid from adhering to and depositing on the surfaces of the light source and receiver. Since the inner wall of the tube body corresponding to the light source and receiver is relatively smooth, cleaning is facilitated. Particles remaining within the tube body can be removed simply by flushing with the test liquid with low turbidity. This allows automatic cleaning during normal use of the automatic cleaning device, extending the service life and minimizing measurement errors caused by deposition. Both the light source and receiver require connection to a circuit board for operation; connecting them to the same circuit board simplifies the structure and reduces costs. A deflecting element offsets the direction of the outgoing light relative to the incoming light, allowing the incoming light from the light source to reach the receiver located adjacent to the light source after several total reflections from the deflecting element. This allows the light source and receiver to be connected to the same circuit board. The main light from the light source propagates radially along the tube body to reach the deflecting element, ensuring that the actual light intensity used during detection is the highest intensity at the center of the light source, improving energy efficiency and minimizing performance losses. The above structural design makes the overall structure of the turbidity sensor relatively simple and makes it less likely for suspended matter to settle, thereby improving detection accuracy and extending service life.

[0017] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Schematic diagram of the axial cross-sectional structure of the turbidity sensor shown in the first embodiment of the present invention;

[0019] Figure 2 Schematic diagram of the top view of the turbidity sensor shown in the first embodiment of the present invention;

[0020] Figure 3 This is a schematic diagram of the detection results of two turbidity sensors shown in Example 1 of the present invention.

[0021] Legend: 1-tube body, 11-positioning part, 2-circuit board, 3-light source, 31-infrared lamp, 32-visible lamp, 4-receiver, 41-infrared receiver, 42-visible receiver, 5-refractive element, 51-connecting surface, 52-first reflecting surface, 53-second reflecting surface, 54-transition surface, 55-reflective material. DETAILED DESCRIPTION

[0022] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0023] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0024] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0025] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0026] The turbidity sensor claimed in the present application includes a tube 1, a circuit board 2, a light source 3, a receiver 4, and a refracting element 5. The light source 3 and receiver 4 are disposed outside the tube 1 and connected to the circuit board 2. The circuit board 2 is disposed on the side of the tube 1 away from the refracting element 5. The liquid to be tested is filled within the tube 1. The light source 3 is configured to emit incident light. At least a portion of the incident light directly passes through the liquid to be tested and reaches the refracting element 5. After being totally reflected several times by the refracting element 5, it forms an outgoing light beam that propagates in a straight line within the liquid to be tested. The receiver 4 is positioned corresponding to the outgoing light beam and is configured to detect the intensity of the received outgoing light beam. The incident light beam is the principal light beam emitted by the light source 3 and propagates radially along the tube 1.

[0027] The tube body 1 is configured to accommodate the liquid to be measured, with the light source 3 and receiver 4 positioned outside the tube body 1. This allows the light source 3 and receiver 4 to be separated from the liquid to be measured, preventing particles carried by the liquid from adhering to and depositing on the surfaces of the light source 3 and receiver 4. Since the inner wall of the tube body 1 corresponding to the light source 3 and receiver 4 is relatively smooth and easy to clean, particles remaining within the tube body 1 can be removed simply by flushing the liquid to be measured with low turbidity. This allows automatic cleaning during normal use of the automatic cleaning device, helping to extend the service life and suppress measurement errors caused by deposition. Both the light source 3 and receiver 4 need to be connected to the circuit board 2 for operation. Connecting them to the same circuit board 2 simplifies the structure and reduces costs. The refracting element 5 offsets the direction of the outgoing light relative to the incoming light, allowing the incoming light emitted by the light source 3 to reach the receiver 4 located adjacent to the light source 3 after several total reflections by the refracting element 5. This makes it possible for the light source 3 and receiver 4 to be connected to the same circuit board 2. The principal light beam from light source 3 propagates radially along tube body 1 to reach light-refraction element 5, ensuring that the light intensity actually utilized during detection is the strongest at the center of the light source. This improves energy utilization and minimizes performance loss. This structural design simplifies the overall structure of the turbidity sensor and reduces the risk of suspended matter deposition, thereby improving detection accuracy and extending its service life.

[0028] In some embodiments, the tube body 1 is constructed as a tubular structure with both ends open, the light source 3 and the receiver 4 are arranged along the axial direction of the tube body 1, and the emitted light propagates along the radial direction of the tube body 1.

[0029] By connecting the inlet and outlet pipes of the test liquid through the tube body 1, turbidity detection is performed simultaneously with the test liquid transfer, simplifying the structure and facilitating real-time testing of the test liquid. Both incident and outgoing light rays propagate in a straight line along the radial direction of the tube body 1, which helps to increase the optical path and, in turn, the detection precision. By arranging the light source 3 and receiver 4 along the axial direction of the tube body 1, both incident and outgoing light rays are perpendicular to the tube wall, suppressing light refraction. Furthermore, both incident and outgoing light rays are aligned directly with the refractive element 5, which helps to reduce light loss during propagation.

[0030] In some embodiments, the tube body 1 is constructed as a transparent structure and has a smooth inner wall. The refractive element 5 is fitted and connected to the outer wall of the tube body 1 and has a first reflecting surface 52 and a second reflecting surface 53. The first reflecting surface 52 and the second reflecting surface 53 are both facing the inner wall of the tube body 1. At least part of the incident light directly passes through the liquid to be tested, and forms a transfer light after being reflected by the first reflecting surface 52. The transfer light directly hits the second reflecting surface 53 and is reflected again to form an outgoing light.

[0031] By fitting the refraction element 5 to the outer wall of the tube 1, the first and second reflective surfaces 52, 53 are isolated from the test liquid, preventing the deposition of suspended particles. By providing the first and second reflective surfaces 52, 53, the transferred light is transmitted only within the refraction element 5, preventing the transferred light from passing through the interface between the tube 1 and the refraction element 5, which would cause refraction and loss, thus simplifying the optical path.

[0032] In some embodiments, the deflecting element 5 is made of the same material as the tube body 1 and is constructed in the same arc-shaped structure as the tube body 1. The deflecting element 5 has a connecting surface 51 that fits against the outer wall of the tube body 1. The ends of the connecting surface 51 are respectively connected to a first reflective surface 52 and a second reflective surface 53. Using the same material helps reduce energy loss when light propagates between the deflecting element 5 and the tube body 1.

[0033] In some embodiments, the refractive element 5 is integrally constructed with the tube body 1, eliminating the connection interface and helping to reduce transmission loss.

[0034] In some embodiments, the deflecting member 5 is detachably connected to the tube body 1 , and a central angle of the deflecting member 5 is greater than 180°.

[0035] In some embodiments, the tube body 1 is made of polycarbonate, and the angle between the second reflective surface 53 and the axial direction of the tube body 1 is any value between 40° and 55°, for example, any value between 40°, 45°, 50° and 55°. The condition for total reflection at the interface is sin(θ)=n 空气 / n 管体 , where θ is the angle between the incident light and the interface, n 空气 is the refractive index of air, which is approximately 1, n 管体 is the refractive index of the tube material. When the tube is made of polycarbonate, n 管体 The value of is 1.586, which helps to ensure the reflectivity of the refractive element 5 and reduce the measurement error caused by partial projection by constraining the angle.

[0036] In some embodiments, the angle between the first reflective surface 52 and the axial direction of the tube body 1 is 45°, so that the transferred light propagates along the axial direction, which helps to simplify the optical path and reduce energy loss.

[0037] In some embodiments, the first reflective surface 52 and / or the second reflective surface 53 of the refracting element 5 are covered with a reflective material 55 , which helps to improve the reflectivity when it is difficult to achieve total reflection of light at the interface between the tube body 1 material and the atmosphere.

[0038] In some embodiments, multiple light sources 3 form incident light with visible light and infrared light, respectively, which are used to detect the turbidity and color depth of the test liquid. Detecting the test liquid by the two dimensions of turbidity and color depth helps to improve the accuracy of the evaluation of the test liquid.

[0039] Please refer to the following examples for details.

[0040] Example 1:

[0041] See Figure 1 and Figure 2 The turbidity sensor shown in a preferred embodiment of the present application includes a tube body 1, a circuit board 2, a light source 3, a receiver 4, and a deflecting element 5. Both the tube body 1 and the deflecting element 5 in this embodiment are constructed of transparent PVC material, making it easy to observe the suspended matter deposition on the inner wall of the tube body 1 from the outside, allowing for timely cleaning or replacement.

[0042] The tube body 1 is a linear, open-ended tubular structure with a diameter of 7 mm. The openings at both ends are smaller in diameter and connect to the inlet and outlet pipes via threads. Its inner wall is highly smooth, making it less susceptible to the adhesion of suspended matter. A rectangular, planar positioning portion 11 is formed on one side of the tube body 1's axial midsection. Positioning portion 11 is perpendicular to the radial direction of the tube body 1 and has positioning markings on its surface.

[0043] The refractive element 5 includes a connecting surface 51, a first reflecting surface 52, a second reflecting surface 53, and a transition surface 54. The connecting surface 51 fits onto the outer wall of the tube body 1, and the transition surface 54 is sleeved outside the connecting surface 51 and coaxial with the connecting surface 51. The first reflecting surface 52 and the second reflecting surface 53 are both constructed as arcuate surfaces, connected between the connecting surface 51 and the transition surface 54, and are both inclined toward the connecting surface 51. In this embodiment, the angles between the first reflecting surface 52 and the second reflecting surface 53 and the transition surface 54 are both 45°. When the refractive element 5 is cut along its axial direction, the resulting cross-section is an isosceles trapezoid. The refractive element 5 in this embodiment has a central angle of 270° and is sleeved onto the outer side of the tube body 1 so that its opening corresponds to the positioning portion 11 of the tube body 1. The refractive element 5 is then removably connected to the tube body 1 by edge sealing. The large central angle of the deflector 5 improves the stability of the connection and reduces the difficulty of installation. It also ensures that the first and second reflective surfaces 52, 53 are aligned with the positioning portion 11 of the tube body 1, reducing the risk of optical path misalignment due to alignment errors. Positioning relative to the tube body 1 can be achieved simply by determining the axial position using markings on the tube body 1, reducing the difficulty of positioning. The deflector 5 also includes reflective material 55. In this embodiment, reflective paper is used. The reflective material 55 is pasted onto the first and second reflective surfaces 52, 53, with the reflective surface facing the inside of the deflector 5, thereby reducing light loss during the reflection process.

[0044] The circuit board 2 is a flexible printed circuit board (PCB). The light source 3 and receiver 4 are both attached to the surface of the circuit board 2 and electrically connected to the external system through the circuit board 2. The side of the circuit board 2, where the light source 3 and receiver 4 are connected, is attached to the positioning portion 11 of the tube body 1. Positioning marks ensure accurate positioning, and the light source 3 and receiver 4 are arranged along the axial direction of the tube body 1. The light source 3 emits incident light perpendicularly through the tube body 1. As the incident light passes through the test liquid inside the tube body 1, some of it is scattered. The remaining portion extends radially along the tube body 1, passes perpendicularly through the tube body 1 again, enters the refracting element 5, and is directed toward the first reflective surface 52. After reflection, it reaches the second reflective surface 53, reflects again, and then passes directly into the test liquid. The remaining light, after some scattering, is directed radially along the tube body 1, becoming the outgoing light. This outgoing light passes perpendicularly through the tube body 1 and reaches the receiver 4. The intensity of the outgoing light detected by the receiver 4 is used to determine the turbidity of the test liquid. In this embodiment, the optical path is twice the diameter of the tube body 1, which helps improve the sensitivity of turbidity detection. The total reflection performed by the refracting element 5 ensures that the central light intensity of the light source 3 is utilized during the detection process, which helps to improve the optical utilization efficiency.

[0045] In this embodiment, the light source 3 includes an infrared lamp 31 for emitting infrared rays and a visible lamp 32 for emitting white light, and the infrared lamp 31 and the visible lamp 32 are arranged along the axial direction of the tube body 1. The receiver 4 includes an infrared receiver 41 corresponding to the infrared lamp 31 and a visible receiver 42 corresponding to the visible lamp 32, and the infrared receiver 41 and the visible receiver 42 are also arranged along the axial direction of the tube body 1. Since infrared light is not sensitive to color depth, the turbidity T is represented by the change ratio of the infrared light intensity, and the color depth T' is represented by the change ratio ds of the visible light minus the effect of turbidity T, that is, T'=(ds-k (T) ×T) / (1-k (T) ×T), where k (T) is the coefficient that changes with T, which is calculated by and , and the formula is:

[0046]

[0047] The specific meanings and calculation methods of the parameters in the formula are described below and are not detailed here. Converting the one-dimensional contamination data into two-dimensional data, representing turbidity and color depth respectively, allows for a more detailed assessment of the contamination status of the liquid, helping to improve the accuracy of the assessment of the test liquid.

[0048] Purchase an existing infrared through-beam turbidity sensor and prepare zero-turbidity water that meets national standards. Use the zero-turbidity water as the control group. Use the zero-turbidity water to dilute and prepare formazine standard solutions of varying concentrations. Test using both the through-beam method and the patented method. Use the light intensity obtained from the control group as the control value, and the light intensity obtained from each standard solution as the test value. Calculate the percentage of the difference between the control and test values relative to the control value as the light intensity change rate. Plot the turbidity test results of the two detection methods on a graph, with turbidity as the horizontal axis and the light intensity change rate as the vertical axis. See [see ] for details. Figure 3 , it can be seen that this patented solution has higher sensitivity than the through-beam solution.

[0049] The patented solution was used to analyze the turbidity and color depth dimensions respectively. The test results are shown in Table 1 below.

[0050] Table 1:

[0051] Standard turbidity NTU 0 50 250 450 750 1050 1250 Standard color depth 0％ 1.34％ 6.52％ 12.21％ 20.39％ 27.96％ 31.94％ Infrared light intensity change rate 0％ 4.76％ 20.62％ 33.63％ 48.56％ 59.72％ 65.45％ Visible light intensity change rate 0％ 5.80％ 24.54％ 39.50％ 55.75％ 67.07％ 72.32％ <![CDATA[k (T) ]]> 0.9551 0.9497 0.9347 0.9243 0.9146 0.9089 0.9066 Color depth T' 0％ 1.34％ 6.52％ 12.21％ 20.40％ 27.98％ 31.93％

[0052] In Table 1 above, k (T) The color depth T' is obtained by calculation. The specific calculation method is shown below.

[0053] Since white diatomaceous earth is insoluble in water, the color depth of white diatomaceous earth turbid solutions of different turbidities is the same, so the color depth is defined and calibrated by the white diatomaceous earth turbid solution. In this application, the color depth is defined by detecting the difference in the visible light intensity change rate between the test solution of the same turbidity and the white diatomaceous earth turbid solution, and the ratio of the corresponding total light intensity. Among them, the standard color depth of formazine standard solution of different turbidity is the standard value obtained in advance. Before performing the color depth test, the turbidimeter needs to be calibrated with white diatomaceous earth turbid solutions of different concentrations. When the infrared light intensity change rate of the white diatomaceous earth turbid solution is detected to be infinitely close to 100%, the visible light intensity change rate detected is about 90%, that is, the constant k e The value is 0.9, which is a constant measured based on the optical system of this turbidimeter. Using a formazine standard solution with a turbidity of 50 as the calibration solution, its standard color depth T'0 is 1.34%. The corresponding ds value and T value are tested and the obtained values are substituted into the calculation formula, which is:

[0054]

[0055] Among them, ds T0The ds value of the calibration solution is 5.80% in this example and is a constant. T'0 corresponds to the standard color depth value of the calibration solution and is 1.34% in this example and is a constant. T0 corresponds to the T value of the calibration solution and is 4.76% in this example and is a constant. T is the T value obtained by testing the test solution and represents the turbidity. The formula is:

[0056]

[0057] Substitute the value of T into the formula to get k (T) The value of ds-k (T) ×T) / (1-k (T) × T), and obtain the detection value of color depth T'.

[0058] From Table 1 and Figure 3 It can be seen from the figure that the turbidity sensor in this embodiment can accurately characterize the turbidity and color depth of the liquid to be tested at the same time.

[0059] The beneficial effects of the present invention include: the light source 3, receiver 4, and refractive element 5 are all disposed outside the tube body 1, separated from the test liquid, which inhibits the deposition of suspended matter in the test liquid on the surface of the turbidity sensor, thereby extending the service life of the sensor. The optical path and structural design extend the optical path, thereby improving detection sensitivity, simplifying the structure and reducing costs. The contamination status of the test liquid is determined based on turbidity and color depth using visible and infrared light, helping to improve the accuracy of the test liquid assessment.

[0060] Example 2:

[0061] The only difference between this embodiment and the first embodiment is that the tube body 1 and the refractive element 5 in this embodiment are integrally constructed. The refractive element 5 in this embodiment is constructed as a trapezoidal columnar prism structure as a whole and is embedded in the outer wall of the tube body 1. The first reflecting surface 52 and the second reflecting surface 53 are both constructed as planes, and both are opposite to the positioning portion 11 of the tube body 1.

[0062] Example 3:

[0063] The only difference between this embodiment and the first embodiment is that, in this embodiment, the infrared lamp 31 and the infrared receiver 41 correspond to one refracting member 5 , and the visible lamp 32 and the visible receiver 42 correspond to another refracting member 5 .

[0064] Example 4:

[0065] The only difference between this embodiment and the first embodiment is that the second reflecting surface 53 is not provided in this embodiment, and the angle between the first reflecting surface 52 and the radial direction of the tube body 1 is 30°. The incident light propagating along the radial direction of the tube body 1 is reflected by the first reflecting surface 52 to form an outgoing light with an angle with the radial direction of the tube body 1, and finally reaches the receiver 4.

[0066] Embodiment 5:

[0067] The only difference between this embodiment and the first embodiment is that the infrared lamp 31 and the infrared receiver 41 are not provided in this embodiment.

[0068] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0069] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A turbidity sensor, characterized in that: The invention comprises a tube body (1), a circuit board (2), a light source (3), a receiver (4) and a refractive element (5), wherein the light source (3) and the receiver (4) are arranged outside the tube body (1) and connected to the circuit board (2), and the circuit board (2) is arranged on a side of the tube body (1) away from the refractive element (5). The liquid to be tested is filled in the tube body (1), and the light source (3) is used to emit incident light, at least part of which directly passes through the liquid to be tested and reaches the refractive element (5). After being totally reflected by the refractive element (5) several times, an outgoing light is formed which propagates in a straight line in the liquid to be tested. The position of the receiver (4) corresponds to the outgoing light and is used to detect the intensity of the received outgoing light. The incident light is the main light emitted by the light source (3), and the incident light propagates in the radial direction of the tube body (1).

2. The turbidity sensor according to claim 1, wherein The tube body (1) is constructed as a tubular structure with both ends open, the light source (3) and the receiver (4) are arranged along the axial direction of the tube body (1), and the emergent light propagates along the radial direction of the tube body (1).

3. The turbidity sensor according to claim 2, wherein The tube body (1) is constructed as a transparent structure. The refractive element (5) is attached to the outer wall of the tube body (1) and has a first reflecting surface (52) and a second reflecting surface (53). The first reflecting surface (52) and the second reflecting surface (53) are both oriented toward the inner wall of the tube body (1). At least a portion of the incident light directly passes through the liquid to be tested and forms a transit light after being reflected by the first reflecting surface (52). The transit light directly strikes the second reflecting surface (53) and is reflected again to form the outgoing light.

4. The turbidity sensor according to claim 3, wherein The refractive element (5) is made of the same material as the tube body (1), and its overall structure is an arc-shaped structure of the tube body (1). The refractive element (5) has a connecting surface (51) that is attached to the outer wall of the tube body (1), and the two ends of the connecting surface (51) are respectively connected to the first reflecting surface (52) and the second reflecting surface (53).

5. The turbidity sensor according to claim 4, wherein The deflecting element (5) and the tube body (1) are integrally constructed.

6. The turbidity sensor according to claim 4, wherein The deflecting member (5) is detachably connected to the tube body (1), and the central angle of the deflecting member (5) is greater than 180°.

7. The turbidity sensor according to claim 4, wherein The tube body (1) is made of polycarbonate, and the angle between the second reflective surface (53) and the axial direction of the tube body (1) is any value between 40° and 55°.

8. The turbidity sensor according to claim 7, wherein The included angle between the first reflecting surface (52) and the axial direction of the tube body (1) is 45°.

9. The turbidity sensor according to claim 3, wherein The first reflecting surface (52) and / or the second reflecting surface (53) of the refracting element (5) are covered with a reflective material (55).

10. The turbidity sensor according to claim 1, wherein The plurality of light sources (3) respectively form the incident light beams with visible light and infrared light, and are respectively used to detect the turbidity and color depth of the liquid to be tested.

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